The present invention relates to data input devices. More particularly the present invention relates to energy efficient implementation of cordless input devices such as a computer mouse.
In the art of electrical appliances and devices, there is a continuing drive and desire for energy efficiency. Such desire is more acute for portable devices dependent on replaceable batteries for energy. For example, cordless devices for computers and workstations such as cordless mice and keyboards are increasing in popularity. These devices are not tethered to a computer and typically use one or more replaceable batteries as their energy source. Batteries provide a limited supply of power. Therefore, the batteries are replaced periodically for continual use of the devices. Energy efficiency is desired in such devices to decrease power consumption thus increasing battery life leading to lower cost of operation. Further, increases in battery life reduce adverse impact on the ecology associated with waste disposal problems of many batteries. This is because many types of batteries include toxic material. In this document, for convenience of discussion and illustration, a cordless computer mouse is used as an example of an electrical device for which increased energy efficiency is desired.
In an existing technique to increase the energy efficiency of the cordless mouse, the device is configured to operate at two modes of operation—an active mode and a sleep mode. In the active mode, the mouse operates at full operational capacity and consumes the full operation amount of energy. Further, in the active mode, the mouse provides an instantaneous response (or very close to an instantaneous response) to user inputs and movements. When a period of inactivity is detected, the mouse enters the sleep mode where portions of the mouse's circuitry are rendered inactive thereby reducing energy consumption.
During the sleep mode, the mouse periodically monitors its sensors to detect any movement or input from the user. To monitor its sensors, much of the inactivated portions of the mouse are activated, thus consuming power for the duration of the monitoring activity. If movement or input is detected, then the mouse wakes up from the sleep mode and enters the active mode. During the sleep mode, the period of time between the monitoring activities determines the degree to which the energy is consumed and the responsiveness of the mouse to the user input. On the one hand, frequent monitoring provides for better responsiveness of the mouse to the user input. On the other hand, frequent monitoring consumes more energy thus reducing effectiveness of the energy conserving sleep mode.
Consequently, there remains a need for better techniques and devices to minimize power consumption while providing sufficient responses to users.